The invention relates generally to coupling devices and, more specifically, to a device for coupling tubular members including a sheet member having a first end and a second end where the first end and the second end are operatively arranged to overlap one another to form a substantially cylindrically shaped coupling.
Essentially, a typical joint for metal ducting (coupling a pair of aligned tubular members) is formed using two pipes with opposing ends of each pipe laid end-to-end, pushed together and then secured by the use of screws. By the nature of the product, particularly large metal ducting at high elevation, usually installed in ceilings, it has been very labor intensive and time consuming to join tubular members (where one person has to move a ladder back and forth from one side of the tubular member to the other, or two people using two ladders have to drive screws simultaneously into pipe). Thus, labor costs have a significant impact on this traditional manner of joining pipe. In addition to labor costs, often times this procedure causes the pipe to bend and does not provide a clean seal. There is the additional concern of alignment of large diameter pipe. As the pipe diameters increase, the range of tolerances also increases, which can result in xe2x80x9cout of roundxe2x80x9d and xe2x80x9cgapxe2x80x9d conditions.
Expansion or contraction devices to hold the tubular members together are known in the art. One acknowledged problem is the difficulty of being able to force the coupling member into the tubular member to be joined, particularly with larger sized tubular members. Another problem encountered is that of holding coupling devices in place between tubular members (pipes, ducts, etc.) to be joined prior to and during expansion of the coupling.
One solution to this problem is taught in U.S. Pat. No. 4,927,189, which discloses an expanding coupling device that requires using two threaded members to effect expansion. This device consists of a cylindrical member where the ends of the sheet forming the tube overlap. In the preferred embodiment, the expansion of the device is effected by two threaded members, each affixed to the cylinder by straps that circumferentially encompass the cylinder. In other embodiments, the expanding device relies on a screw and socket assembly. This means that to expand the coupling device, the expansion device first must be pivoted into place and then a socket wrench must be employed to effect expansion. Conversely, to release the expanding device, the expansion device must first be loosened using a socket wrench and then pivoted up. This device requires the use of multiple straps that circumferentially encompass the cylinder and an expansion device that must be pivoted into place.
Various devices have been designed to accommodate the coupling of a pair of aligned tubular members. The invention disclosed in U.S. Pat. No. 5,769,459 (Graff et al.) relies on rubber coated, helical sleeves that are inserted inside of a pipe to seal a leak. The expandable sleeves are expanded by means of an inflatable air cushion or a mechanical mounting device. When the expanded sleeves come to rest against the inner pipe walls, sealing rings are installed. The sleeves are held in place by a pinion meshing with a row of teeth and a resilient locking bolt.
European Patent Application No. 0069098 (Andersson) teaches a cylindrical coupler with overlapping ends for extension and expansion of the coupling device. This invention teaches the use of triangular shaped lugs into which a screw is inserted. This device uses a sheet of rubber, or other resilient material, of such a length that before the coupling device is extended, the cloth resides on the surface of the device in folds that become unfolded as the device is expanded. This device is held in an unexpanded state by a steel band that extends circumferentially around the device. A weak point is built into the steel band so that when the device is expanded, the weak point breaks allowing for further expansion of the coupling device.
The internal expansion device disclosed by German Patent No. 28 41 572 (Schlimbach) includes two beads (or protuberances) on the outside, circumferential edges of the cylindrical device that are made to fit into mating recesses in the internal surface of the pipes that are being coupled. In this device, the edges of the cylinder do not overlap, but instead they seem to abut. Attached to the inside of the cylinder is an extra piece of material that is used to cover the opening made when the cylinder edges are moved away from each other as the cylinder is expanded to provide a coupling.
Disadvantages of the above-described devices include excessive internal diameter restrictions; difficulty in handling and manipulating; the requirement of special skills and/or tools to connect and disconnect; strict inside pipe diameter tolerances in order to form a sealed union; the lack of gasket sealing integrity under field conditions; failure under high internal pressures; and, a lack of flexibility.
Hence, there has existed a longfelt need for an improved coupling device for tubular members such as ducts and pipes.
The present invention generally comprises a device for coupling tubular members including a sheet member having a first end and a second end where the first end and the second end are operatively arranged to overlap one another to form a substantially cylindrically shaped coupling, an abutment member mounted to the sheet member proximate the second end thereof, a male threaded member, a female member pivotably mounted proximate the first end of the sheet member and arranged for pivoting rotation about a pivot point, where the female member is arranged to threadably engage the threaded male member, and the male member is operatively arranged to abut the abutment member, wherein the male threaded member is operatively arranged to rotate in a first direction to abut the abutment member and expand the substantially cylindrically shaped coupling, and at least one clip fixedly attached to an outer surface of the substantially cylindrically shaped coupling, in which the clip functions to hold the coupling device in engagement with the tubular members during coupling.
A general object of the present invention is to provide a coupling device that, when in the contracted condition can be easily inserted into pipe ends, and, when in an expanded condition provides a tight seal between adjacent pipes.
Another object of the present invention is to provide ease of assembly and disassembly.
Still another object of the present invention is to provide a coupling device that can be reused in its entirety.
Still a further object of the present invention is to provide a coupling device that is economical to manufacture and labor efficient to use.
Still another further object of the present invention is to provide a coupling device with one pivoting threaded member to effect expansion.